10
however if the system has an unusually high water
content, it may be necessary to provide additional
expansion capacity (see 6.24).
3A.6.6 FILLING POINT
A method for initial filling of the system and
replacing water lost during servicing etc. has been
provided. You should ensure this method of filling
complies with the local water authority regula-
tions.
3A.6.7 LOW PRESSURE SEALED SYSTEM
An alternative method of filling the system would
be from an independent make-up vessel or tank
mounted in a position at least 1-metre above the
highest point in the system and at least 5-metres
above the boiler (see fig. 5).
The cold feed from the make-up vessel or tank
must be fitted with an approved non-return valve
and stopcock for isolation purposes. The feed pipe
should be connected to the return pipe as close to
the boiler as possible.
3A.6.8 FREQUENT FILLING
Frequent filling or venting of the system may be
indicative of a leak. Care should be taken during
the installation of the appliance to ensure all
aspects of the system are capable of withstanding
pressures up to at least 3 bar.
3A.7
ELECTRICAL SUPPLY
The appliance is supplied for operation on 230V @
50Hz electrical supply; it must be protected with a
3-amp fuse. The method of connection to the
mains electricity supply must allow for complete
isolation from the supply. The preferred method is
by using a double-pole switch with a contact
separation of at least 3mm. The switch must only
supply the appliance and its corresponding con-
trols, i.e. time clock, room thermostat, etc.
3A.8
SHOWERS
If the appliance is intended for use with a shower,
the shower must be thermostatically controlled
and be suitable for use with a combination boiler.
3A.9
MOUNTING ON A COMBUSTIBLE
SURFACE
If the appliance is to be fitted on a wall of combus-
tible material, a sheet of fireproof material must
protect the wall.
3A.10 TIMBER FRAMED BUILDINGS
If the appliance is to be fitted in a timber framed
building, it should be fitted in accordance with I.S.
813 and local Building Regulations.
The Institute of Gas Engineers publication (IGE/
UP/7) ‘Guide for Gas Installations in Timber Frame
Buildings’ gives specific advice on this type of
installation.
3A.11 INHIBITORS
Vokera recommend that an inhibitor - suitable for
use with copper and aluminium heat exchangers -
is used to protect the boiler and system from the
effects of corrosion and/or electrolytic action.
The inhibitor must be administered in strict
accordance with the manufacturers’ instructions*.
*Water treatment of the complete heating system
- including the boiler - should be carried out in
accordance with I.S. 813 and the Domestic Water
Treatment Association’s (DWTA) code of practice.
3A.12 DECLARATION OF CONFORMITY
A Declaration of Conformity (as defined in I.S.
813) must be provided on completion of the in-
stallation.
A copy of the declaration must be given to the
responsible person and also to the gas supplier if
required.
